Approach tendency and threat display as related to social status of Siamese fighting fish,Betta splendens

Abstract

Forty-eight male Betta splendens were assigned to three groups of 16 (eight pairs) each. In two of the groups, pairs of fish were first allowed to fight until a dominance-subordinance relationship was established. Then each subject was tested on measures of time spent in approach and threat display toward either (1) its own pair member, with which it was experienced and familiar (Group EF), or toward (2) another combat-experienced fish, with which it was unfamiliar (Group EV). A third group of inexperienced and unfamiliar individuals (Group IV) were first exposed to their own mirror images and then tested for approach and threat-display duration. Pairs of these fish were then allowed to fight until dominance was determined. The three major findings were: (a) Dominant subjects approached and displayed significantly more than subordinates in all three groups; (2) Dominant subjects of Group IU did not differ significantly from dominants in the other two groups with respect to time spent in approach and display; and (3) Fish exposed to mirrors prior to combat required significantly fewer sessions to establish dominance than fish not receiving mirror exposure. Results suggest that dominant fish can be distinguished on the basis of their approach tendency and threat-display scores prior to actual physical combat. An habituation model of dominance determination was proposed.The threat display of the male Siamese fighting fish, Betta splendens, is characterized by extension of the gill covers, erection of the fins, a deepening of body color, and a sequence of vibrating body movements (Simpson, 1968). This threat display is reliably emitted whenever a male encounters an unfamiliar male conspecific, and it will even occur with considerable vigor in response to a male model, or in response to the male's own mirror image (Johnson, 1972). Furthermore, Bettas will

Predictors of dominance in male Betta splendens..

“…Also, the current findings provide a plausible explanation for the result of Meliska et al (1975). Meliska et al (1975) arranged sue- cessive male-male pairings, with each of these encounters lasting 15 min. They appear to have found reliable individual differences in display, a finding supported by the current study.…”

On the Relationship between Aggression and Social Dominance

“…I have presented evidence that, in at least some animal species, when this procedure is adopted, the measures of aggression and dominance status are not correlated. However, in two studies in which this protocol was used, aggression scores were found to predict dominance status (MELISKA et al 1975;EVANS 1985). In two other studies (BAENNINGER 1970;BARLOW et al 1986) aggressive behavior was found to predict dominance relationships under some conditions but not under others.…”

Effects of prior social experience on agonistic responding by Siamese fighting fish (Betta splendens)

“…The finding, in Experiment 1, that subordinate fish are less inclined to view conspecifics than are more dominant fish, is consistent with the results of others. For example, when dominant and subordinate fish were permitted to view either familiar or unfamiliar opponents, Meliska et al (1975) reported that dominant fish spent more time approaching and displaying to their visual opponents than did subordinate fish. Also, Baenninger (1970) reported that dominant fish performed at a higher operant level than submissive fish when reinforcement was the opportunity to view a mirror.…”

“…Prior social experience has been operationally defined in a number of ways, including dominant and subordinate roles resulting from paired encounters (Baenninger, 1968(Baenninger, ,1970Lobb & McCain, 1976;Meliska, Meliska, Hoyenga, Hoyenga, & Ward, 1975), prior visual experience with a conspecific (Meliska & Meliska, 1976;Miley & Burack, 1977), and visual and combat experience with responsive or passive conspecifics and nonconspecifics (Johnson & Johnson, 1973).…”